Mercury switch



Feb. 26, 1957 J. w. GARDEN MERCURY SWITCH Filed March 13 m 0 V Pd R. M mm m m m w s e m w 4 0 J Y B F Unifiid States Patent MERCURY SWITCH James W. Carden, Munday, Tex.

Application March 13, 1956, Serial No. 571,326

2 Claims. (Cl. 200-152) This invention relates to electrical make and break devices and more particularly to a novel electrical switch employing an electrical conducting fluid.

The primary object of the present invention resides in the provision of a highly eflicient switch for controlling electrical circuits which is extremely durable and is so constructed as to eliminate any pitting or corrosion of contacts which would otherwise severely shorten the life of a switch.

A further object of the invention resides in the provision of an electrical switch which employs a flexible container for mercury whereby the mercury will serve as a conducting fluid between a pair of contacts. Incorporated in the invention is means for compressing the receptacle whereby the level of the mercury will be raised from below the contacts to a point where the contacts are immersed in the mercury.

One of the special features of the invention lies in the provision of a resilient plate which normally pushes or urges the push button type actuator into an outwardly disposed position ready for use and which plates cooperates with a back plate to provide opposed planar surfaces for engagement with the receptacle having the mercury therein and for compressing the receptacle.

Another special feature of construction of the invention lies in the fact that the means utilized for suspending the receptacle having the mercury therein are terminals to which electrical conductors are connected and from which the contacts are suspended.

Still further objects and features of this invention reside in the provision of a mercury switch that is simple in construction, highly efiicient in operation, which may be employed for various divergent purposes to complete operative electrical circuits, being specially adapted for manual operation as a door-bell and the like, and which is relatively inexpensive to construct.

These, together with the various ancillary objects and features of the invention which will become apparent as the following description proceeds, are attained by this mercury switch, a preferred embodiment of which has been illustrated in the accompanying drawings, by way of example only, wherein:

Figure l is a perspective view of the mercury switch comprising the present invention;

Figure 2 is a vertical sectional view in an enlarged scale as taken along the plane of line 2-2 of Figure 1;

Figure 3 is a vertical sectional detail view similar to that of Figure 2 but showing the switch in an actuated position; and

Figure 4 is a rear elevational view of the invention with part of the back plate thereof being broken away to show the other portions of the invention in detail.

With continuing reference to the accompanying drawings wherein like reference numerals designate similar parts throughout the various views, reference numeral 10 generally designates the mercury switch comprising the present invention which includes a housing 12 adapted to be secured to any suitable surface as at 14 by means of a pair of screws or other fasteners 16 extending through suitable countersunk apertures as at 18 provided in the housing 12. The housing 12 is also provided with an aperture 20 therethrough through which an actuator 22 in the form of a push button member extends. The actuator 22 includes an engaging portion 24 especially adapted to be engaged by the fingers for depressing and actuating the mercury switch. The actuator 22 further includes an enlarged substantially cylindrical portion 26 which provents the complete withdrawal of the actuator 22 from the housing 12 in order to provide a comparatively large engaging surface for engagement of the actuator with the resilient plate 28. The resilient plate 28 may be formed of any suitable metal or the like and is preferably embedded as at St? in the housing 12.

Secured to the housing 12 by means of a pair of screws 32 and 3 which serve as terminals is the upper cross portion 36 of a substantially T-shaped receptacle 38 formed of any suitable synthetic plastic or other similar material which is filled with mercury as at 40. The quantity of mercury in the flexible receptacle 38 is not sufficient for the uppermost level thereof as at 42 to rise into engagement with the pair of contacts 44 and 46 which are suspended from the terminals 32 and 34 and in electrical con-tact therewith. Suitable conductors as at 48 are adapted to be secured to the terminals 32 and 34 and are connected to an alarm device of any suitable nature or the electrical circuit to be actuated as well as to a source of electrical power.

The casing 12 includes a back plate 50 which has an oifset portion 52 inwardly depressed towards the actuator 22. This offset portion 52 is in alignment with the actuator 22 and with the plate 28 so that upon depression of the actuator 22, the receptacle 38 is compressed whereby r the level of fluid rises to the level as is indicated at 54 immersing the contacts 44 and 46 in the conductive fluid and completing the operative electrical circuit.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A switch comprising an outer housing having an aperture therethrough, an actuator positioned at least partially within said housing and having an engaging portion thereof extending outwardly of said housing through said aperture, a flexible receptacle having a quantity of mercury therein, means securing said receptacle to said housing in alignment with said actuator, a resilient plate disposed between said actuator and said receptacle normally urging said engaging portion of said actuator outwardly of said housing, a pair of contacts in said receptacle, the level of said quantity of mercury being normally below said contacts, said housing having a back plate, said receptacle being disposed between said back plate and said resilient plate, said back plate having an offset portion extending towards said actuator in alignment with said resilient plate and said actuator, said actuator when operated urging said resilient plate into engagement with said receptacle to compress said receptacle between said resilient plate and said offset portion thereby raising the level of said quantity of mercury to immerse said contacts in said quantity of mercury.

2. A switch comprising an outer housing having an aperture therethrough, an actuator positioned at least partially within said housing and having an engaging portion thereof extending outwardly of said housing through said aperture, a flexible receptacle having a quantity of mereury therein, means securing said receptacle to said housingin alignment with said actuator, a resilient plate .disposed between said actuator and said receptacle normally urging said engaging portion of said actuator outwardly df;saidhousing, a painof contacts in said receptacle, the levelbfs'aid quantityof mercury being normally below saidgcontacts, said housing'having aback, plate, said receptacle being disposed between said back plate and said resilient plate, said back plate having an offset portion extending towards said actuator in alignment with said resilient plate and said actuator, said actuator when operated urging said resilient plate into engagement with said receptacle to compress said receptacle between said resilient plate and saidottset portion thereby raising the level of said quantity of mercury to immerse said contacts insaid References Cited in the file of this patent UNITED STATES PATENTS 1,365,754 Wahl Jan. 18, 1921 2,195,199 Becker Mar. 26, 1940 2,486,785 Hutcheon Nov. 1, 1949 

